i say leave them, if they are growing fine where they are, dont risk anything, then wen they are budding, wait between a week or two and go out and get all the buds. dont touch them one bit b4 otherwise the people may try to move them. the reason you harvest between a week or two after they start to bud is because once they start, it takes around 2 weeks for it to fully bud, the long you leave it, the more bud obviously. so you want to get a lot of bud, but at the same time leave it long enough w/o the owners harvesting the plants. if they harvest early you can try tell the owners you saw them and see if you can get some bud, but i wouldnt force them, usually a grower has some sort of protection. if they wont give you any, see if they can grow a plant for u next year or somthin. in most cases if you find some1s weed, dont take any, and dont tell any1 bout it, they may give you some, sell some for cheap to you, or help you grow.